Engine-driven working machine

ABSTRACT

An engine-driven working machine capable of favorably reducing exhaust sound (that is, noise) is provided. An engine-driven working machine 10 is a generator in which an engine 15 and a muffler 67 are housed in an inside 13 of an outer case 12. The generator 10 includes a tail pipe 68 that is provided at a lower portion 67a of the muffler 67, a discharge port 37 that is disposed above the tail pipe 68, and a baffle plate 84 that is disposed to face the discharge port 37. The discharge port 37 is formed in the outer case 12. Further, cooling air that is sent from a cooling fan 17 is guided to below the muffler 67 with the baffle plate 84.

INCORPORATION BY REFERENCE

The present application claims priority under 35 U.S.C. § 119 toJapanese Patent Application No. 2016-051821 filed on Mar. 16, 2016. Thecontent of the application is incorporated herein by reference in itsentirety.

BACKGROUND OF THE INVENTION

Field of the Invention

The present invention relates to an engine-driven working machine havingan engine and a muffler housed in an inside of an outer case.

Description of the Related Art

As an engine-driven working machine, there is known a generator in whicha muffler is housed in an inside of an outer case, a tail pipe isextended to a silencing chamber from the muffler, and an exhaust port ofthe tail pipe is opened to be laterally oriented to face a dischargeport. Further, a sound absorbing member is provided in the silencingchamber. According to the engine-driven working machine, exhaust gas isguided to the silencing chamber from the exhaust port of the tail pipe,and the exhaust gas which is guided is discharged to an outside of theouter case from the exhaust port via the silencing chamber (refer toJapanese Utility Model Laid-Open No. 59-181232, for example).

According to the engine-driven working machine of Japanese Utility ModelLaid-Open No. 59-181232, it is possible to insulate exhaust sound of theexhaust gas in the silencing chamber to some extent, by guiding theexhaust gas to the silencing chamber from the exhaust port of the tailpipe. Further, the sound absorbing member is provided in the silencingchamber, and therefore, it is possible to absorb the exhaust sound ofthe exhaust gas to some extent by the sound absorbing member.

However, in the engine-driven working machine of Japanese Utility ModelLaid-Open No. 59-181232, the exhaust port of the tail pipe is opened tobe laterally oriented to face the discharge port. Thereby, it isdifficult to insulate the exhaust sound of the exhaust gas favorably inthe silencing chamber. Consequently, a contrivance to reduce the exhaustsound (that is, noise) is required, and there is left a room forimprovement from this point of view.

SUMMARY OF THE INVENTION

The present invention addresses a problem to provide an engine-drivenworking machine that is capable of favorably reducing exhaust sound(that is, noise).

A first aspect of the present invention provides an engine-drivenworking machine in which an engine and a muffler are housed in an insideof an outer case, including a tail pipe that is provided at a lowerportion of the muffler, a discharge port that is disposed above the tailpipe, and is formed in the outer case, and a baffle plate that isdisposed to face the discharge port, and guides cooling air that is sentfrom a cooling fan, to below the muffler.

As above, the tail pipe is provided at the lower portion of the muffler,and the discharge port is disposed above the tail pipe. Consequently,the exhaust port of the tail pipe can be separated downward from thedischarge port. Exhaust gas is discharged from the discharge port.Thereby, the exhaust gas can be discharged to a position that isseparated from the discharge port, so that insulation of exhaust soundis enhanced, and the exhaust sound (that is, noise) can be favorablyreduced.

Further, the baffle plate is disposed to face the discharge port, andcooling air is guided to below the muffler with the baffle plate.Thereby, the cooling air can be guided to the tail pipe and surroundingsof the tail pipe. Consequently, the members around the tail pipe can beprevented from being deteriorated by exhaust heat.

In a second aspect of the present invention, the engine-driven workingmachine preferably further includes a protector that covers the mufflerand the tail pipe, and a sound absorbing member that is provided on aninner surface of the protector.

As above, the muffler and the tail pipe are covered with the protector,and the sound absorbing member is provided on the inner surface of theprotector. Thereby, the exhaust sound that is discharged from thedischarge port can be absorbed by the sound absorbing member, and theexhaust sound can be reduced more favorably.

Further, by guiding the cooling air to the tail pipe and thesurroundings of the tail pipe with the baffle plate, the cooling air canbe guided to the protector and the sound absorbing member. Thereby, theprotector and the sound absorbing member can be prevented from beingdeteriorated by the exhaust heat.

In a third aspect of the present invention, in the tail pipe, an exhaustport of the tail pipe is preferably opened to intersect an openingdirection of the discharge port.

As above, the exhaust port of the tail pipe is opened to intersect theopening direction of the discharge port. Thereby, the orientation of thedischarge port can be shifted from the traveling direction of theexhaust sound. Thereby, insulation of the exhaust sound is enhanced, andthe exhaust sound can be reduced more favorably.

According to the present invention, the tail pipe is provided at thelower portion of the muffler, and the discharge port is disposed abovethe tail pipe. Thereby, exhaust sound (that is, noise) can be reducedfavorably.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of an engine-driven working machineaccording to the present invention;

FIG. 2 is a perspective view illustrating a fuel tank and a cover unitin FIG. 1;

FIG. 3 is an exploded perspective view illustrating the cover unit inFIG. 2;

FIG. 4 is a sectional view taken along line 4-4 in FIG. 1;

FIG. 5 is a sectional view taken along line 5-5 in FIG. 1;

FIG. 6 is a view seen from an arrow 6 in FIG. 2;

FIG. 7 is an exploded perspective view illustrating a fan cover, ashroud and an undercover in FIG. 3;

FIG. 8 is a sectional view taken along line 8-8 in FIG. 1;

FIG. 9 is a sectional view taken along line 9-9 in FIG. 1;

FIG. 10 is a perspective view of a state where a rear case and a mufflercover are removed from the engine-driven working machine in FIG. 9, seenfrom a rear;

FIG. 11 is a view explaining an example in which intake air flows to acombustion chamber from an intake system of the engine-driven workingmachine according to the present invention, and exhaust gas flows to anexhaust system from the combustion chamber;

FIG. 12 is a view explaining an example of cooling a power generatingunit, a cylinder and a muffler with cooling air that is sent from acooling fan of the engine-driven working machine according to thepresent invention; and

FIG. 13 is a view explaining an example of decreasing exhaust sound andfurther cooling a protector and a sound absorbing material in theengine-driven working machine according to the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

A best mode for carrying out the present invention will be describedhereinafter on the basis of the accompanying drawings.

Note that “a front (Fr)”, “a rear (Rr)”, “a left (L)” and “a right (R)”shown in the drawings are set based on an operation panel 27 side of anengine-driven working machine 10 as the front (Fr).

Here, an example of applying the engine-driven working machine 10according to the present invention to “a generator 10” in an embodimentwill be described, but it is also possible to apply the engine-drivenworking machine 10 to other working machines such as a mowing machine, asnowplow, and a tiller.

Embodiment

The engine-driven working machine (more specifically, the generator) 10according to the embodiment will be described.

As illustrated in FIGS. 1 and 2, the generator 10 includes an outer case12 that forms an outer frame of the generator 10, an engine 15 (refer toFIG. 3) that is housed in an inside 13 of the outer case 12, a powergenerating unit (working unit) 16 that is provided at a left side of theengine 15, a cooling fan 17 that is provided at a left side of the powergenerating unit 16, a recoil starter 18 that is provided at a left sideof the cooling fan 17, and a cover unit 20 that covers the engine 15.

The recoil starter 18 is covered with a recoil cover 19.

Further, the generator 10 includes an intake system (an intake systemcomponent) 22 that communicates with the engine 15, an exhaust system(an exhaust system component) 24 (refer to FIG. 4) that is connected tothe engine 15, a fuel tank 26 that is disposed in front of the engine15, and the operation panel 27 that is provided on a front wall 12 a ofthe outer case 12.

According to the generator 10, the engine 15 (refer to FIG. 3) drives bymanually rotating the recoil starter 18. A crankshaft 41 (refer to FIG.5) rotates by the engine 15 driving. A rotor of the power generatingunit 16 is connected to the crankshaft 41. Thereby, the rotor of thepower generating unit 16 rotates by the crankshaft 41 rotating.

The rotor of the power generating unit 16 rotates, whereby anelectromotive force is generated in the rotor and a stator, and powergeneration is performed in the power generating unit 16. Adirect-current power that is generated in the power generating unit 16is converted into an alternating-current power in an inverter, and issupplied to an outside from a connector 28 on the operation panel 27.

Further, the cooling fan 17 is connected to the rotor of the powergenerating unit 16. Thereby, the rotor of the power generating unit 16rotates, whereby the cooling fan 17 rotates. The cooling fan 17 rotates,whereby outside air is sucked into the inside 13 from an outside 14 ofthe outer case 12, and the outside air which is sucked is sent to theintake system 22, the engine 15 and the exhaust system 24 as coolingair.

Here, the generator 10 (that is, the engine 15) drives, and therebyvibration occurs around the crankshaft 41 (refer to FIG. 5). Thevibration that occurs around the crankshaft 41 is suppressed by thegenerator 10.

Means for suppressing the vibration that occurs around the crankshaft 41will be described in detail later.

The outer case 12 includes a left case 31 that forms a left half part ofthe outer case 12, a right case 32 that forms a right half part of theouter case 12, a front case 33 that is mounted to front end portions ofthe left case 31 and the right case 32, a rear case 34 that is mountedto rear end portions of the left case 31 and the right case 32, and anundercover 35 (refer to FIG. 3) that supports the respective cases 31 to34.

The rear case 34 has a substantially rectangular discharge port 37(refer to FIG. 9) in an upper portion of a rear wall 34 a. That is, theupper portion of the rear wall 34 a is opened to be in a substantiallyrectangular shape at the discharge port 37.

The outer case 12 is formed into a substantially rectangular shape inplan view so as to extend in a longitudinal direction (one direction) bythe left case 31, the right case 32, the front case 33, the rear case 34and the undercover 35. More specifically, the outer case 12 is formedinto a substantially rectangular frame body shape that extends in thelongitudinal direction.

The crankshaft 41 (refer to FIG. 5) is disposed to intersect (morespecifically, be orthogonal to) the longitudinal direction of the outercase 12.

The engine 15 (refer to FIG. 3), the cover unit 20, and the fuel tank 26are housed in the inside 13 of the outer case 12. In this state, a tankcap 29 of the fuel tank 26 is protruded (exposed) to above the outercase 12.

Further, the front wall 12 a of the outer case 12 is formed by a frontwall of the front case 33. The operation panel 27 is provided on thefront wall 12 a of the front case 33.

Front rubber support portions 38 (only the front rubber support portion38 at a left side is illustrated) are attached to a left and right sidesof a front end portion of the undercover 35. Further, rear rubbersupport portions 39 (only the rear rubber support portion 39 at a leftside is illustrated) are attached to a left and right sides of a rearend portion of the undercover 35. The generator 10 is supported on afloor surface or the like with the front rubber support portions 38 atthe left and right sides and the rear rubber support portions 39 at theleft and right sides.

Here, the outer case 12 is formed into the substantially rectangularshape in plan view so as to extend in the longitudinal direction.Thereby, a space between the front end portion and the rear end portionof the undercover 35 is secured to be large.

Thereby, a space L1 between the front rubber support portion 38 that isattached to the front end portion of the undercover 35, and the rearrubber support portion 39 that is attached to the rear end portion ofthe undercover 35 is secured to be large.

As illustrated in FIGS. 3 and 4, the engine 15 is housed in the inside21 of the cover unit 20. Further, the cover unit 20 is housed in theinside 13 of the outer case 12.

The engine 15 includes the crankshaft 41 (refer to FIG. 5) that extendsin a lateral direction of the outer case 12, a cylinder 42 that isdisposed above the crankshaft 41, a cylinder head 43 that is provided atan upper end portion of the cylinder 42, an intake port 44 and anexhaust port 45 that are provided at the cylinder head 43, and a valvemechanism 46 that is connected to the crankshaft 41.

As illustrated in FIG. 5, the crankshaft 41 is disposed to intersect(more specifically, be orthogonal to) the longitudinal direction of theouter case 12. In other words, the crankshaft 41 is disposed to extendin a lateral direction of the outer case 12.

That is, in a state where the engine 15 is housed in the inside 13 ofthe outer case 12, the engine 15 is disposed to be laterally orientedwith respect to the outer case 12.

As illustrated in FIGS. 4 and 5, the valve mechanism 46 includes a drivetiming pulley 51 that is provided coaxially with the crankshaft 41, adriven timing pulley 52 that is provided above the drive timing pulley51, and a cam drive belt 53 that is laid across the drive timing pulley51 and the driven timing pulley 52.

The drive timing pulley 51, the driven timing pulley 52 and the camdrive belt 53 are housed in an inside of a cam case 54. The cam case 54is formed integrally with the cylinder 42.

Further, the valve mechanism 46 includes a camshaft 56 that supports thedriven timing pulley 52, and an intake valve 57 and an exhaust valve 58that drive by a cam of the camshaft 56. That is, the valve mechanism 46is an overhead camshaft (OHC) type mechanism.

The intake valve 57 is disposed at one side (that is, one side in adirection intersecting the camshaft 56) of the camshaft 56. Further, theexhaust valve 58 is disposed at the other side (that is, the other sidein the direction intersecting the camshaft 56) of the camshaft 56.

Further, the camshaft 56 of the valve mechanism 46 is disposed parallelwith the crankshaft 41. Thereby, the intake valve 57 is disposed at afront side of the camshaft 56. Further, the exhaust valve 58 is disposedat a rear side of the camshaft 56.

Thereby, the intake port 44 is disposed at a front side of the cylinderhead 43 (that is, the engine 15) in the longitudinal direction of theouter case 12. Further, the exhaust port 45 is disposed at a rear sideof the cylinder head 43 (that is, the engine 15) in the longitudinaldirection of the outer case 12.

A carburetor 61 of the intake system 22 is directly connected to theintake port 44. The carburetor 61 is disposed at a front side (that is,a front side of the engine 15) of the intake port 44, and at an outerside of the cover unit 20. More specifically, a fan cover 81 (describedlater) is included in the cover unit 20, and the carburetor 61 isdisposed outside the fan cover 81.

Here, the outer case 12 is formed to be substantially rectangular inplan view to extend in the longitudinal direction. Thereby, a space 64is easily secured in the front side of the intake port 44. Thereby, thespace 64 in which the carburetor 61 is disposed can be securedrelatively easily.

Further, the carburetor 61 is disposed at the intake port 44 side, andthe carburetor 61 is directly connected to the intake port 44. Thereby,flow resistance of intake air that flows to the intake port 44 from thecarburetor 61 is suppressed to be small.

Further, an air cleaner 62 of the intake system 22 is connected to thecarburetor 61. The air cleaner 62 is disposed at a left side of theengine 15, above the cooling fan 17 and the power generating unit 16,and outside the cover unit 20.

More specifically, the air cleaner 62 is disposed outside the fan cover81 that is included in the cover unit 20.

An exhaust passage (an exhaust manifold) 66 of the exhaust system 24 isconnected to the exhaust port 45. The exhaust passage 66 is disposed ata rear side (that is, the rear side of the engine 15) of the exhaustport 45. Further, a muffler 67 of the exhaust system 24 is connected tothe exhaust passage 66.

The muffler 67 is disposed at the rear side (that is, the rear side ofthe engine 15) of the exhaust port 45, and is housed in the inside 21 ofthe cover unit 20. A tail pipe 68 is provided at a lower portion 67 a ofthe muffler 67. The tail pipe 68 communicates with the muffler 67.

The tail pipe 68 is raised upward from the lower portion 67 a of themuffler 67, and an exhaust port 68 a is opened upward at an upper end ofthe tail pipe 68. Exhaust gas is guided to the tail pipe 68 from thelower portion 67 a of the muffler 67, and the guided exhaust gas passesthrough the tail pipe 68 and is discharged from the exhaust port 68 a.

The tail pipe 68 is provided at the lower portion 67 a of the muffler67, whereby the exhaust port 68 a of the tail pipe 68 is disposed at alower portion 34 b side of a rear wall 34 a of the rear case 34. Thedischarge port 37 (refer to FIG. 9) is opened at an upper portion of therear wall 34 a.

Thereby, the discharge port 37 is disposed above the exhaust port 68 aof the tail pipe 68.

Here, the outer case 12 is formed to be substantially rectangular inplan view to extend in the longitudinal direction. Thereby, a space 71is easily secured at a rear side of the exhaust port. Thereby, the space71 in which the exhaust passage 66 and the muffler 67 are disposed canbe secured relatively easily.

Furthermore, the muffler 67 is disposed at the exhaust port 45 side.Thereby, the exhaust passage 66 that allows the muffler 67 tocommunicate with the exhaust port 45 does not have to be curved greatly,and can be simplified. Thereby, the flow resistance of the exhaust gasthat flows in the exhaust passage 66 can be suppressed to be small.

In this way, the engine 15 is disposed to be laterally oriented in theinside 13 of the outer case 12, whereby the space 64 in which thecarburetor 61 is disposed can be easily secured, and the space 71 inwhich the exhaust passage 66 and the muffler 67 are disposed can beeasily secured. Thereby, the outer case 12 does not have to be upsizedto secure the space 64 and the space 71.

Further, the engine 15 is disposed to be laterally oriented, whereby theflow resistances of intake air and exhaust gas are suppressed to besmall, and the output power of the engine 15 is secured. Thereby, theengine 15 does not have to be upsized to secure the output power of theengine 15.

By suppressing upsizing of the outer case 12 and upsizing of the engine15, the generator 10 can have a slim structure suitable to be carried.

Further, the power generating unit 16 is disposed at the left side ofthe engine 15 and at an extension line 73 side of the crankshaft 41.More specifically, the power generating unit 16 is provided on a sameaxis as the axis of the crankshaft 41.

Further, the cooling fan 17 is disposed at the left side of the powergenerating unit 16 and at the extension line 73 side of the crankshaft41. More specifically, the cooling fan 17 is provided on a same axis asthe axis of the crankshaft 41.

Here, an outlet port 75 from which a cooling air is blown from thecooling fan 17 is disposed to face the carburetor 61. That is, theoutlet port 75 from which the cooling air is blown is disposed at a leftside of the cylinder 42 and at a front side of the cylinder 42. In otherwords, the outlet port 75 from which the cooling air is blown isdisposed at a left front side of the cylinder 42.

Thereby, the cooling air that is sent from the outlet port 75 of thecooling fan 17 is guided by the cover unit 20 to be led to the powergenerating unit 16 from the left front side of the cylinder 42. Thecooling air that is guided to the power generating unit 16 is guided bythe cover unit 20 and is guided to the front side of the cylinder 42 ina curved manner via the power generating unit 16. Thereby, the powergenerating unit 16 and the cylinder 42 can be cooled with the coolingair.

Further, the cooling air that is guided to the front side of thecylinder 42 is guided by the cover unit 20 and is guided to the muffler67 via the cylinder 42. Thereby, the power generating unit 16, thecylinder 42 and the muffler 67 can be efficiently cooled with thecooling air that is sent from the outlet port 75 of the cooling fan 17.

As illustrated in FIGS. 3 and 6, the engine 15, the carburetor 61 andthe muffler 67 are housed in the inside (refer to FIG. 4) of the coverunit 20.

The cover unit 20 includes the fan cover 81 that is provided at the leftside of the engine 15, a shroud 82 that is provided at a right side ofthe engine 15, a muffler cover 83 that is provided at respective rearend portions of the fan cover 81 and the shroud 82, and a baffle plate84 (also refer to FIG. 10) that is provided in front of the mufflercover 83.

The cooling fan 17 and the power generating unit 16 are covered with thefan cover 81. Further, the shroud 82 is provided at an opposite side (aright side) of the fan cover 81. The engine 15 is covered with theshroud 82 from the right side.

Further, the muffler cover 83 is provided at a rear end portion of thefan cover 81 and a rear end portion of the shroud 82. The muffler 67 iscovered with the muffler cover 83. The baffle plate 84 is provided inthe inside 21 of the cover unit 20 and in front of the muffler cover 83.

The fan cover 81, the shroud 82, the muffler cover 83 and the baffleplate 84 will be described in detail later.

In a state where the fan cover 81 and the shroud 82 are integrallyconnected, the fan cover 81 and the shroud 82 include first mountingmeans 85 and second mounting means 86.

The first mounting means 85 is formed at lower front portions of the fancover 81 and the shroud 82 which are integrally connected. Morespecifically, the first mounting means 85 is configured by a first covermounting portion 87 that is formed at a lower front portion of the fancover 81, and a first shroud mounting portion 88 that is formed at alower front portion of the shroud 82.

Further, the second mounting means 86 is formed at lower rear portionsof the fan cover 81 and the shroud 82 which are integrally connected.More specifically, the second mounting means 86 is configured by asecond cover mounting portion 91 that is formed at a lower rear portionof the fan cover 81, and a second shroud mounting portion 92 that isformed at a lower rear portion of the shroud 82.

The undercover 35 is disposed under the fan cover 81 and the shroud 82.The fan cover 81 and the shroud 82 are supported by the undercover 35.

The undercover 35 is formed to be substantially rectangular in planview, and has a first support portion 94 that is provided at a front endportion 35 a side (one end side in one direction of the outer case), anda second support portion 95 that is provided at a rear end portion 35 bside (the other end side in the one direction of the outer case).

The first support portion 94 includes a first left support portion 96that is provided at a front left end portion side of the undercover 35,and a first right support portion 97 that is provided at a front rightend portion side of the undercover 35.

The second support portion 95 includes a second left support portion 98that is provided at a rear left end portion side of the undercover 35,and a second right support portion 99 that is provided at a rear rightend portion side of the undercover 35.

As illustrated in FIGS. 7 and 8, the first cover mounting portion 87 andthe first shroud mounting portion 88 are interposed between the firstleft support portion 96 and the first right support portion 97. In thisstate, the respective mounting portions 87 and 88 are connected to therespective support portions 96 and 97 with a bolt 102 and a nut 103.

Further, a spacer 104 is fitted onto the bolt 102. Furthermore, a leftshock absorbing portion 105 is interposed between the first covermounting portion 87 and the spacer 104. A right shock absorbing portion106 is interposed between the first shroud mounting portion 88 and thespacer 104.

Thereby, the first mounting means 85 is mounted to the first supportportion 94. In this state, a front mounting portion 31 a of the leftcase 31 and a front mounting portion 32 a of the right case 32 arefastened together to the first support portion 94 with the bolt 102 andthe nut 103.

Similarly, the second mounting means 86 is mounted to the second supportportion 95. In this state, a rear mounting portion 31 b (refer toFIG. 1) of the left case 31 and a rear mounting portion (notillustrated) of the right case 32 are fastened together to the firstsupport portion 94 with a bolt and a nut.

Thereby, the left case 31 is mounted to a left side of the undercover35, and the right case 32 is mounted to a right side of the undercover35.

In this state, the fan cover 81 and the shroud 82 are integrallyassembled. Further, the left case 31 and the right case 32 of the outercase 12 are integrally assembled.

As above, the first support portion 94 and the second support portion 95are formed on the undercover 35. Further, the first mounting means 85and the second mounting means 86 are formed at the fan cover 81 and theshroud 82. Furthermore, the first mounting means 85 is mounted to thefirst support portion 94, and the second mounting means is mounted tothe second support portion.

Thereby, the fan cover 81 and the shroud 82 are mounted to theundercover 35, and therefore, it is not necessary to prepare mountingmembers separately. Thereby, the number of components of the generator10 can be further reduced.

Next, the fan cover 81 and the shroud 82 will be described.

As illustrated in FIG. 4, the crankshaft 41 is disposed by being causedto intersect the longitudinal direction of the outer case 12. Further,the cooling fan 17 is provided on the extension line 73 of thecrankshaft 41. Here, in the longitudinal direction of the outer case 12,the muffler 67 is provided at a rear side of the engine 15.

Thereby, the muffler 67 is disposed in a position that is deviated froman axis line (that is, the extension line 73 of the crankshaft 41) ofthe cooling fan 17.

Thereby, it becomes possible to provide the fan cover 81 at the coolingfan 17 side, and provide the shroud 82 at an opposite side of the fancover 81. Accordingly, the engine 15, the power generating unit 16 andthe cooling fan 17 can be covered with the two members that are the fancover 81 and shroud 82, and therefore, the number of components can bedecreased.

Thereby, the number of assembly steps of the fan cover 81 and the shroud82 can be decreased, and cost reduction can be achieved.

In an ordinary power generator, a fan cover and a shroud are formedseparately. Further, the shroud is divided into a left shroud and aright shroud. Consequently, the number of components increases, and thisbecomes hindrance to decrease of the number of assembly steps of the fancover and the shroud.

As illustrated in FIG. 7, the fan cover 81 has a cylindrical coverportion 111 that covers the cooling fan 17 and the power generating unit16 (refer to FIG. 3), a left shroud portion 112 that is integrallyformed from a top portion of the cover portion 111 to a lower rearportion, the first cover mounting portion 87 that is formed at a lowerfront portion of the cover portion 111, and the second cover mountingportion 91 that is formed at a lower rear portion of the cover portion111.

The left shroud portion 112 has a first left wall 112 a that is raisedupward from the top portion of the cover portion 111, a left top portion112 b that is projected to above the cylinder head 43 (refer to FIG. 3)from an upper side of the first left wall 112 a, a second left wall 112c that is raised upward from an inner side of the left top portion 112b, and a left rear shroud portion 112 d that is integrally formed atrespective rear sides of the first left wall 112 a, the left top portion112 b and the second left wall 112 c.

The left shroud portion 112 is disposed at the left side of the engine15 (refer to FIG. 4). Here, a concave portion 114 is formed by the leftshroud portion 112 and the cover portion 111. The air cleaner 62 (referto FIG. 2) is disposed in the concave portion 114.

The shroud 82 has a right side wall 115 a that is disposed at a rightside of the engine 15 (refer to FIG. 3), a right bottom portion 115 bthat is projected along the undercover 35 from a lower side of the rightside wall 115 a, a right top portion 115 c that is projected to theengine 15 side from an upper side of the right side wall 115 a, a frontwall 115 d that is projected to the engine 15 side from the right sidewall 115 a, the first shroud mounting portion 88 that is formed at afront portion of the right bottom portion 115 b, and the second shroudmounting portion 92 that is formed at a rear portion of the right bottomportion 115 b.

The engine 15 is covered with the shroud 82 from the right side.

As illustrated in FIGS. 4 and 5, the fan cover 81 and the shroud 82 areintegrally assembled. In this state, a rear opening 116 is formed atrear end portions of the fan cover 81 and the shroud 82. The mufflercover 83 is mounted to the rear opening 116.

Further, a space is formed in the inside 21 (that is, the inside of thecover unit 20) of the fan cover 81, the shroud 82 and the muffler cover83. The engine 15, the power generating unit 16, the cooling fan 17 andthe muffler 67 are housed in the space of the inside 21.

In this state, the crankshaft 41 is disposed by being caused tointersect the longitudinal direction of the outer case 12. That is, theengine 15 is disposed to be laterally oriented with respect to the outercase 12. The outer case 12 is formed to be substantially rectangular inplan view that extends in the longitudinal direction.

Consequently, the space L1 between the front rubber support portion 38and the rear rubber support portion 39 is secured to be large.

Here, the generator 10 (that is, the engine 15) drives, wherebyvibration occurs around the crankshaft 41. Consequently, the engine 15is disposed to be laterally oriented with respect to the outer case 12,and thereby the vibration around the crankshaft 41 can be caused to actin the longitudinal direction of the outer case 12.

Thereby, the vibration of the engine-driven working machine 10 can befavorably suppressed by the front rubber support portion 38 and the rearrubber support portion 39. Accordingly, the vibration of the generator10 during an operation can be suppressed to be small, andmerchantability of the generator 10 is enhanced.

The muffler 67 is caused to communicate with the exhaust port 45 via theexhaust passage 66, and is disposed at the rear side of the exhaust port45 and the engine 15. In this state, the muffler 67 is disposed in therear opening 116.

The muffler 67 and the tail pipe 68 are covered with the muffler cover83. The muffler cover 83 includes a protector 117 that is mounted to therear opening 116, and a sound absorbing material 118 that is mounted toan inner surface 117 a of the protector 117.

As illustrated in FIG. 9, the protector 117 is formed to cover themuffler 67 and the tail pipe 68 from behind. The protector 117 has alouver 121 in a substantially rectangular shape in outer shape that isformed at an upper portion. The louver 121 is located inside thedischarge port 37 of the rear case 34, and is disposed to face thedischarge port 37.

Furthermore, in the protector 117, an opening peripheral edge portion117 b is integrally mounted to the rear end portion 81 a of the fancover 81 and the rear end portion 82 a of the shroud 82 (also, refer toFIG. 10).

Further, the discharge port 37 is disposed above the exhaust port 68 aof the tail pipe 68. That is, the discharge port 37 and the louver 121are disposed above the exhaust port 68 a of the tail pipe 68. Thereby,the exhaust port 68 a of the tail pipe 68 is separated downward from thedischarge port 37.

Thereby, exhaust gas from the exhaust port 68 a can be exhausted to aposition that is away from the discharge port 37 and the louver 121.

Here, the exhaust port 68 a of the tail pipe 68 is opened to intersectthe opening direction (the arrow A direction) of the discharge port 37.Thereby, an orientation of the discharge port 37 can be shifted from thetraveling direction of the exhaust sound (an arrow B direction).Thereby, isolation of the exhaust sound can be further enhanced with theprotector 117.

Furthermore, the sound absorbing material 118 is mounted to the innersurface 117 a of the protector 117. Thereby, sound of the exhaust gasthat is exhausted from the exhaust port 68 a can be absorbed by thesound absorbing material 118.

As illustrated in FIGS. 9 and 10, the baffle plate 84 is provided in theinside 21 of the cover unit 20. More specifically, the baffle plate 84is integrally mounted to substantially upper half portions of the rearend portion 81 a of the fan cover 81 and the rear end portion 82 a ofthe shroud 82 in a state where the baffle plate 84 is laid on theopening peripheral edge portion 117 b of the protector 117.

In this state, the baffle plate 84 is disposed to face the louver 121and the discharge port 37. A lower end 84 a of the baffle plate 84 isdisposed in a vicinity of a top of a top end 67 b of the muffler 67, andextends in a lateral direction along the top end 67 b.

Further, a lower left portion 84 b of the baffle plate 84 is disposedbetween the muffler 67 and the rear end portion 81 a of the fan cover81. Further, the baffle plate 84 is inclined with a falling gradienttoward the rear.

Further, similarly to the baffle plate 84, the muffler 67 is inclinedwith a falling gradient toward the rear from a vicinity of the lower end84 a of the baffle plate 84.

The baffle plate 84 is provided at substantially upper half portions ofthe rear end portion 81 a of the fan cover 81 and the rear end portion82 a of the shroud 82. Thereby, an upper half part of the inside 21 ofthe cover unit 20 is partitioned into a space 21 a at the engine 15 sideand a space 21 b at the louver 121 side with the baffle plate 84.

Thereby, the cooling air that is sent from the cooling fan 17 can beguided to below the muffler 67 with the baffle plate 84.

Meanwhile, in a lower half part of the inside 21 of the cover unit 20,the space 21 a at the engine 15 side and the space 21 b at the louver121 side communicate with each other. In particular, the space 21 a atthe engine 15 side and the space 21 b at the louver 121 side communicatewith each other via a lower space 21 c under a lower portion 67 a of themuffler 67.

Consequently, the cooling air that is guided to below the muffler 67 canbe guided to the space 21 b via the lower space 21 c.

Next, an example in which intake air flows to the combustion chamberfrom the intake system 22 of the engine-driven working machine 10, andexhaust gas flows to the exhaust system 24 from the combustion chamberwill be described based on FIG. 11.

As illustrated in FIG. 11, the carburetor 61 is disposed at the intakeport 44 side, and thereby the carburetor 61 is directly mounted to theintake port 44. Thereby, the flow resistance of intake air C that flowsto the combustion chamber via the intake port 44 from the carburetor 61can be suppressed to be small.

Further, the muffler 67 is disposed at the exhaust port 45 side.Thereby, the muffler 67 is allowed to communicate with the exhaust port45 without curving the exhaust passage 66 significantly. Thereby, theflow resistance of exhaust gas D that flows to the muffler 67 throughthe exhaust port 45 and the exhaust passage 66 from the combustionchamber can be suppressed to be small.

In this way, the flow resistance of the intake air C is suppressed to besmall, and the flow resistance of the exhaust gas D is suppressed to besmall, whereby the output power of the engine 15 can be secured.

Next, an example of cooling the power generating unit 16, the cylinder42 and the muffler 67 with the cooling air that is sent from the coolingfan 17 of the engine-driven working machine 10 will be described basedon FIG. 12.

As illustrated in FIG. 12, the cooling fan 17 rotates like an arrow E,and thereby, outside air is sucked by the cooling fan 17 like an arrowF.

The outside air which is sucked is guided with the fan cover 81, and issent as cooling air like toward the power generating unit 16 from anoutlet port 75 of the cooling fan 17 as an arrow G. The cooling air issent to the power generating unit 16, and thereby, the power generatingunit 16 is cooled with the cooling air.

The cooling air that has cooled the power generating unit 16 is guidedwith the front wall 115 d of the shroud 82 and a cam case 54, and isguided toward the cylinder 42 as an arrow H. The cooling air is guidedto the cylinder 42, and thereby the cylinder 42 is cooled by the coolingair. The cooling air that has cooled the cylinder 42 is guided towardthe muffler like an arrow I. The cooling air is guided to the muffler,and thereby, the muffler is cooled with the cooling air.

Thereby, the power generating unit 16, the cylinder 42 and the muffler67 can be efficiently cooled with the cooling air that is sent from theoutlet port 75 of the cooling fan 17.

Next, examples of decreasing exhaust sound in the engine-driven workingmachine 10, and further cooling the protector 117 and the soundabsorbing material 118 will be described based on FIG. 13.

First, an example of decreasing the exhaust sound in the engine-drivenworking machine 10 will be described.

As illustrated in FIG. 13, the exhaust gas is guided to the muffler 67from the exhaust passage 66 like an arrow J. The exhaust gas that isguided to the muffler 67 passes through the tail pipe 68 and isexhausted from the exhaust port 68 a to the space 21 b like an arrow K.

The exhaust gas that is exhausted passes through the space 21 b and isguided to the louver 121 like an arrow L. The exhaust gas that is guidedto the louver 121 passes through the louver 121 and the discharge port37 and is discharged to the outside 14 of the outer case 12 like anarrow M.

Here, the louver 121 and the discharge port 37 are disposed above theexhaust port 68 a. Consequently, the exhaust port 68 a is separateddownward from the discharge port 37. Thereby, the exhaust gas from theexhaust port 68 a can be exhausted to a position that is away from thedischarge port 37 and the louver 121.

Further, the exhaust port 68 a is opened to intersect the openingdirection (an arrow A direction) of the discharge port 37, and thereby,an orientation of the discharge port 37 can be shifted from a travelingdirection of the exhaust sound.

By exhausting the exhaust gas to the position away from the dischargeport 37 and the louver 121, and shifting the orientation of thedischarge port 37 from the traveling direction of the exhaust sound inthis way, insulation of the exhaust sound can be enhanced with theprotector 117.

Further, the sound absorbing material 118 is mounted on the innersurface 117 a of the protector 117, whereby the sound of the exhaust gasthat is exhausted from the exhaust port 68 a can be absorbed with thesound absorbing material 118.

By insulating the exhaust sound with the protector 117, and absorbingthe exhaust sound with the sound absorbing material 118 in this way, theexhaust sound (that is, noise) can be reduced more favorably. Thereby,the exhaust sound that is transmitted to the outside (that is, theoutside 14 of the outer case 12) of the cover unit 20 can be suppressedto be small.

Next, an example of cooling the protector 117 and the sound absorbingmaterial 118 will be described.

As illustrated in FIG. 13, the cooling air that is sent from the coolingfan 17 (refer to FIG. 10) is guided to the baffle plate 84 side via thecylinder 42 like an arrow N. The cooling air that is guided to thebaffle plate 84 side is guided toward the muffler 67 side (that is, alower side) by the baffle plate 84 like an arrow O.

In particular, the baffle plate 84 is inclined with a falling gradienttoward the rear. Therefore, the cooling air that is guided to the baffleplate 84 side is efficiently guided toward the muffler 67 side with thebaffle plate 84.

The cooling air that is guided to the muffler side is guided to thelower portion 67 a of the muffler 67 via a space 21 d between themuffler 67 and the engine 15 like an arrow P. The cooling air that isguided to the lower portion 67 a of the muffler 67 is guided to thespace 21 b via the lower space 21 c like an arrow Q.

By guiding the cooling air to the space 21 b, the cooling air can beguided to the tail pipe 68, the protector 117 and the sound absorbingmaterial 118. Thereby, the protector 117 and the sound absorbingmaterial 118 can be prevented from being deteriorated by exhaust heat.

The cooling air that is guided to the space 21 b is discharged to theoutside 14 of the outer case 12 via the louver 121 and the exhaust port68 a like an arrow R.

The engine-driven working machine according to the present invention isnot limited to the aforementioned embodiment, and modifications,alterations and the like can be made properly.

For example, in the aforementioned embodiment, the example in which thecarburetor 61 is directly provided at the intake port 44 is described,but the present invention is not limited to this, and it is alsopossible to cause the carburetor 61 to communicate with the intake port44 via the intake passage (the intake manifold).

In this case, the carburetor 61 is also disposed at the intake port 44side, and therefore, the intake passage that causes the carburetor 61 tocommunicate with the intake port 44 does not have to be curvedsignificantly, and can be simplified. Thereby, the flow resistance ofthe intake air that flows in the intake passage is suppressed to besmall, and the output power of the engine can be secured.

Further, in the aforementioned embodiment, the example in which thecrankshaft 41 is disposed orthogonally to the longitudinal direction ofthe outer case 12 is described, but the present invention is not limitedto this. For example, it is also possible to cause the crankshaft 41 tointersect the longitudinal direction of the outer case 12 in an inclinedmanner.

Furthermore, the shapes and the configurations of the generator, theouter case, the engine, the cooling fan, the discharge port, themuffler, the tail pipe, the exhaust port of the tail pipe, the baffleplate, the protector, the sound absorbing member and the like which areshown in the aforementioned embodiment are not limited to the shapes andthe configurations that are illustrated, but can be properly changed.

The present invention is suitable for application to the engine-drivenworking machine that has the engine and the muffler housed in the insideof the outer case, and exhausts exhaust gas from the tail pipe of themuffler.

REFERENCE SIGNS LIST

-   10 Generator (engine-driven working machine)-   12 Outer case-   13 Inside of outer case-   15 Engine-   17 Cooling fan-   37 Discharge port-   67 Muffler-   67 a Lower portion of muffler-   68 Tail pipe-   68 a Exhaust port of tail pipe-   84 Baffle plate-   117 Protector-   117 a Inner surface of protector-   118 Sound absorbing member

What is claimed is:
 1. An engine-driven working machine in which anengine and a muffler are housed in an inside of an outer case,comprising: a tail pipe that is provided at a lower portion of themuffler and communicates with the muffler; a discharge port that isdisposed above an exhaust port of the tail pipe, and is formed in theouter case; a protector that covers the muffler and the tail pipe andhas an opening disposed to face the discharge port; and a baffle platethat is disposed to face the discharge port, extends downward, and alower end of the baffle plate is located in a vicinity of an upper endof the muffler so as to guide cooling air, which is sent from a coolingfan to below the muffler, and the exhaust port of the tail pipe isarranged to be opened upward at a lower part of a space partitioned bythe protector and the baffle plate.
 2. The engine-driven working machineaccording to claim 1, further comprising: a sound absorbing member thatis provided on an inner surface of the protector.
 3. The engine-drivenworking machine according to claim 1, wherein in the tail pipe, anexhaust port of the tail pipe is opened to intersect an openingdirection of the discharge port.
 4. The engine-driven working machineaccording to claim 2, wherein in the tail pipe, an exhaust port of thetail pipe is opened to intersect an opening direction of the dischargeport.